KENNEDY SPACE CENTER, FLA. -- Astronaut Dave Williams dons his wet suit before heading for the National Oceanic and Atmospheric Administration (NOAA) Aquarius Underwater Laboratory. Williams is leading a 17-day undersea mission as part of the NASA Extreme Environment Mission Operations (NEEMO) project. Other members of the mission are astronauts Nicole Stott and Ron Garan, plus Dr. Tim Broderick of the University of Cincinnati. The undersea laboratory is situated three miles off Key Largo in the Florida Keys National Marine Sanctuary, anchored 62 feet below the surface. The astronauts are testing space medicine concepts and moon-walking techniques.